Extreme pressure agent and its preparation

ABSTRACT

A particulate dispersion of an alkali metal borate is prepared by contacting boric acid with an alkali metal carbonate overbased metal sulfonate within an oleophilic liquid reaction medium.

United States Patent 11 1 King et a1.

[ Dec. 30, 1975 [54] EXTREME PRESSURE AGENT AND ITS PREPARATION [75] Inventors: John M. King, San Rafael; Nicolaas Bakker, Pinole, both of Calif.

[73] Assignee: Chevron Research Company, San

Francisco, Calif.

22 Filed: Mar. 22, 1974 211 App]. N0.: 453,898

[52] US. Cl 252/33.4; 252/33 [51] int. CL Cl0M 1/40; ClOM 3/34; C10M 5/22;

C10M 7/38 158] Field of Search 252/33, 33.4, 18, 25

[56] References Cited UNITED STATES PATENTS 6/1961 Hartley et a1. 252/18 3/1966 Wiley et a1 252/33.4

Primary Examiner-Delbert E. Gantz Assistant Examiner-J. Vaughn Attorney, Agent, or FirmG. F. Magdeburger; C. .l. Tonkin [57] ABSTRACT A particulate dispersion of an alkali metal borate is prepared by contacting boric acid with an alkali metal carbonate overbased metal sulfonate within an elecphilic liquid reaction medium.

23 Claims, No Drawings EXTREME PRESSURE AGENT AND ITS PREPARATION DESCRIPTION OF THE INVENTION Numerous additives are incorporated into lubricating oils and greases to enhance their lubricating properties. A wide variety of materials have been employed to increase the load-carrying capacity of lubricants employed under boundary or extreme pressure (EP) conditions. When moving surfaces are separated by oil or a grease, as the load is increased and the clearance is reduced between the surfaces, the condition of boundary, or thin-film, lubrication is reached. Metal-to-metal contact occurs and wear or seizure results. Under these conditions, the effectiveness of lubricants in reducing wear or friction varies widely. At still higher loads, the condition commonly known as extreme pressure lubrication is reached. Scuffing, galling, and rapid wear or seizure may occur. Welding of two contacting surfaces occurs followed by metal transfer (galling) or cleavage and production of metal fragments.

In order to avoid the undesirable effects which result when using an uncompounded lubricant under high load conditions, extreme pressure agents are added. For the most part, the extreme pressure agents have been oil-soluble agents containing a chemically reactive element, e.g., chlorine, sulfur, or phosphorus, which reacts with the metal surface at the high temperatures produced under load conditions. This chemical bond to the EP agent then provides relatively good boundary protection.

Recently, a new type of additive has been developed which, unlike the chemically reactive chlorine, sulfur or phosphorus containing EP agent, does not react with the metal surfaces to become chemically bonded thereto. Instead, this extreme pressure additive is a dispersion of microparticulate alkali metal borates which is believed to deposit on the metal surface a viscous lubricating film. These borates and their preparation ai'e disclosed in US. Pat. No. 3,313,727.

The microparticulate metal borates are prepared by dissolving an alkali metal borate, or its precursors, in water and emulsifying the aqueous solution in oil to form a micro-emulsion. The emulsion is then dehydrated, leaving amorphous or glassy particles of the hydrated alkali metal borate dispersed within the lubricating oil.

Although the borate dispersions prepared in this manner have excellent extreme pressure properties, there is a need to prepare borate dispersions by a method which does not involve the use of a water-in-oil emulsion and its subsequent dehydration. In addition, certain borate dispersions exhibit a compatibility problem with other lubricating oil additives such as phenates, sulfurized fats, and zinc dithiophosphates.

It is therefore an object of this invention to provide an improved method for preparing a dispersion of microparticles of an alkali metal borate in a lubricating oil or grease.

It is an additional object of this invention to provide a method for preparing borate dispersions having EP properties which does not involve the employment of a water-in-oil emulsion.

It is an additional object of this invention to provide a borate dispersion having improved EP properties. An

additional object of this invention is to provide a borate dispersion which has improved compatibility with other lubricating oil additives.

The aforementioned objects and their attendant advantages may be realized by a particulate dispersion of an alkali metal borate prepared by contacting boric acid with an alkali metal carbonate overbased alkali or alkaline earth metal sulfonate within a stable inert oleophilic liquid reaction medium. Overbased materials are characterized by a metal content in excess of that stoichmetrically required by the'reaction of the metal with the particular sulfonic acid. The base ratio is the ratio of the chemical equivalents of excess metal in the product to the chemical equivalents of the metal required to neutralize thesulfonic acid.

By preparing the alkali metal borates by the reaction of boric acid with the alkali metal carbonate overbased alkali or alkaline earth metal sulfonate, the necessity for using a water-in-oil emulsion is avoided. In addition, it was discovered that the borate dispersions prepared by the method of this invention have improved compatibility with other additives which are normally incorporated into lubricating oils and include phenates, sulfurized fats, and zinc dithiophosphates.

DETAILED DESCRIPTION OF THE INVENTION The borate dispersions of this invention are prepared by contacting within an oleophilic reaction medium (1 boric acid and (2) an alkali metal carbonate overbased alkali or alkaline earth metal sulfonate. The resulting alkali metal borate particles prepared by this method are believed to have the empirical formula:

M O-xB O -yI-I O wherein: M is an alkali metal selected from the group consisting of lithium, sodium, and potassium and preferably sodium or potassium; x is a number from 0.8 to 3.5 and preferably from 1.0 to 3.0, and y is a number from 0 to 8; and preferably from 0 to l.

The borate particles prepared by the method of this invention form a stabledispersion in the oleophilic liquid reaction medium. These particles are almost entirely less than 0.1 micron and more usually less than 0.05 micron. The product may be filtered to remove the larger microparticles.

The alkali metal carbonate overbased alkaline earth or alkali metal sulfonates are prepared by overbasing a neutral alkali or alkaline earth metal sulfonate with an alkali metal carbonate.

NEUTRAL METAL SULFONATE The neutral alkali or alkaline earth metal sunfonates which may be overbased in the practice of this invention can comprise any oil-soluble alkali or alkaline earth metal sulfonate. Preferably, these sulfonates are aromatic and have the following generalized chemical formula:

wherein: R is hydrogen or an alkyl having. from to 22 carbons (preferably from to 21) and preferably attached to the benzene ring througha secondarycarbon atom; R1 is .an alkyl havingfro rn 3 to 10 carbons when R is an alkyl :or an' alkyl having from 8. to 22 carbons when R is hydrogen. M1 is an alkali or alkaline earth metal; and p is an integer from -1 to 2 and sufficient to make M1 electro-neutral.

. In a particular embodiment the neutral'metal sulfohate is a dialkylbenzene sulfonate of the above formula wherein R is a straight chain aliphatic hydrocarbon radical of 17' to 21 carbon atoms, usually having at least 2 homologspresent, and having secondary carbon attachment to the benzene ringHand R1 is a branched chain alkyl group of 3 to 10 carbon atoms, more usually from 4 to 9 carbon atoms, having at least 1 homolog sent, and preferably having at leasttwo homologs sent, and there being at least 1 branch 'of. 1' to 2 carbon atoms, more usually of 1 carbon atom,.i.e., methyl, per 2 carbon atoms, along the'longest chain. The attachment of the shorter alkylgroup will generally be secondary or tertiary. Particular compositions have R1 with an average of 5 to 8 carbon atoms. I

Usually, the difference in, average number of carbon atoms between the short and long chain alkyl groups will be at least 10 and more usually at'least l2, and not more than '16. T

The preferred dialkylbenzene sulfonates which fin use in the practice of this invention will generally have small amounts of. monoalkylbenzene sulfonate, wherein the alkyl group is of from. 17 to 21 .carbonatoms, present within the admixture. Preferably, the amount of the monoalkylb'e nzene sulfonate will not exceed 30% and more preferably the monoalkylbenzene sulfonate will not exceed by weightof the total sulfonate. Generally," it will be in the range of about 5 to 20 weight percent.

y he posit ons of the alkyl group and the sulfonate on the benzenering in relation to each other are not critical to this invention. Generally, most of the isomeric poss'ibilites will be encountered with the particular isoniers hav'ihg the least steric hindrance being predominant. Also, there will be a broad spectrum of isomersbased on the carbon of the alkyl group bonded to the benzene ring, depending on the method of preparation and the reactants used in the preparation.

' Illustrative short chain alkyl groups are isopropyl,

tert.-butyl, neopentyl, diisobutyl, dipropenyl, tripropenyl, etc. I

Illustrative of the long chain alkyl groups are hepta: decyl, octadecyl, nonadecyl, eicosyl and heneicosyl, H

The total number of carbon atoms in thealkyl groups will generallybeinthe range of at least about '20 and less than-about 28. While small amounts of the dialkylbenzenes may be outside this range, the average num- The average molecular weights of the alkylated benzenes used to prepare the sulfonate will generally be in the range pf about 350to 460, more usually in the range of about 375. to 4 25. V

The monoalkyl benzenes can be prepared by simply reacting benzene with a mono-olefin in a simple alkylation process. Typical alkylation catalysts include Friedel-Crafts catalysts such as hydrogen fluoride, aluminum chloride, phosphoric acid, etc. The alkylation temperatures will ordinarily be in the range of about 4C (40F) to 38C'(100F.)

The particular dialkyl benzenes can be prepared in substantially the same manner. A description of its preparation is disclosed in U.S. Pat. No. 3,470,097.

The monoor dialkylbenzenes may then be readily sulfonated, usingconventional sulfonation procedures and agents, including oleum, chlorosulfonic acid, sulfur trioxide .(complexed or thin film dilution techniques) and the like,

Various methods may be used to neutralize the sulfonic acid obtained, these methods being extensively described in the art. See for example U.S. Pat. Nos. 2,485,861, 2,402,325,and 2,732,344.

The neutralization step is conveniently conducted by contacting the sulfonated alkyl or dialkyl benzenes with an aqueous alkali metal hydroxide solution. The product is a neutral alkali metal sulfonate. The neutralalkaline earth metal sulfonate is prepared by a simple metal exchange processThe alkali'metal sulfonate is contacted with an alkalineear'th metal salt, typically the halide salt, and the mixtureheate'd. The exchange process may be accomplished'at temperatures of to 150C and contact times of 0.5 to 10 hours, usually from '1 to 3 hours.

Ordinarily, the neutralized product will be mildly overbased, having from about 0.02 to 0.7 mol percent excess of basic metal over that required for neutralizing propyleicosylbenzene sulfonate, potassium or barium tert.-butyl nonadecylbenzene sulfonate, calcium diside chain and an average molecular weight of about t 167 is alkylated ,with a substantially straight chain Cl7-C2l cracked wax alpha-olefin. The molecular weight of the resulting dialkylbehzene rnixture has an average valuein the range of 350 to 450 and preferably 400 to 420.

propenyl octadecylbenzene sulfonate, calcium diisobuty1 octadecylbenzene sulfonate, sodium (propylene trimer) nonadecylbenzene sulfonate, barium isopropyl eicosylbenzene sulfonate, etcl I -O VERBAS1NG OF THE NEUTRAL METAL SULFONATE Various methods of overbasing neutral metal sulfonates have been reported in the literature. See for ex- Pat. NOS. 2,695,910, 3,282,835 and 3,155,616, as well as Canadian Patent-570,814. The preferred method" employs'a method similar to that described in U.S. Pat. No. 3,155,616.

ample U.S.

The overbasing process can be conveniently conducted by charging to asuitabl'e reaction zone the neutral metal sulfonate, and an inert hydrocarbon solvent. An alkali metal base (usually an alkali metal hydroxide) dissolved ina C1 to C4 alkanol is added while the mixture is agitated and maintained at a temperature and, pressure sufficient toremove fromthe liquid mixture by distillation most of the alkanol charged. Carbon dioxide or another suitable acid gas (hydrogen sulfide, sulfur dioxide, etc.) is then contacted with the reaction medium, preferably sparged or bubbled through the liquid mixture. The introduction of the acid gas is continued until its absorption rate into the mixture ceases or substantially subsides. Generally, from 0.2 to 1.6 equiv. and more usually from 0.9 to 1.3 equiv. of acid gas will be absorbed by the mixture for every equivalent of alkali metal base present.

The crude reaction product is then heated to strip out the residual alkanol and water of reaction. The stripping will generally be conducted at temperatures below 150C and usually below 125C.

After stripping the alkanol and water, the product may be filtered.

The stripping of the hydrocarbon diluent will generally be carried out at temperatures below 200C and will usually not exceed 175C, depending on the hydrocarbon diluents used. Preferably, when xylene is used, the temperature will not exceed 150C.

Occasionally, the final product will be filtered again to remove any adventitious particulate matter which may still be present.

In a different embodiment, the hydrocarbon diluent is first stripped and then the product is filtered. Also, further addition of oil may be made to obtain a product having a somewhat lower viscosity. The choice of the particular route will depend on the equipment, the materials used, their physical properties, and the product desired.

The alkanol used, preferably methanol, will generally have from about 0.01 to 1 weight percent water, more usually from about 0.1 to 0.7% water. The alkanol will generally be present from about 0.1 to 20, more usually from about 1 to weight parts per part of alkali metal base.

The hydrocarbon diluent will be one having a boiling point higher than alkanol to permit its retention when the alcohol is removed during processing. The boiling point should generally be less than about 280C and preferably less than about 250C. Usually, the hydrocarbon diluent will form an azeotrope with water. The usual diluents contain aromatic hydrocarbons of 7 to 10 carbon atoms, having boiling points in the range of about 100 to 180C. These include toluene, xylene, cumene and cymene. The hydrocarbonaceous diluent can be present in an amount to form about a 5 to 20 weight percent dispersion of alkali metal base in the initial composition, usually an 8 to weight percent dispersion.

The amount of overbasing varies greatly depending upon the amount of borate dispersion ultimately wanted. Typically from 1 to equivalents of alkali metal base will be used per equivalent of neutral metal sulfonate, more usually from about 5 to 15 equivalents of alkali metal base per equivalent of neutral metal sulfonate. Thus, alkalinity values range from 50 to 460 mg.KOI-I/g, and preferably from about 150 to 300 mg.KOH/g.

It should be recognized that mixtures of alkali metal carbonates may be employed as well as mixtures of alkali and alkaline earth metal sulfonates. Thus, a sodium and potassium carbonate overbased sodium and calcium sulfonate may be present in the same mixture which may be further reacted with the boric acid to form the borate particles of theinstant invention.

OLEOPHILIC REACTION MEDIUM The overbased metal sulfonate is contacted with boric acid within a suitable oleophilic reaction medium. As referred to herein oleophilic is defined as a property of a substance having a strong affinity to oils. The liquid oleophilic medium is generally present in the preparation of the overbased sulfonate and hence extraneous addition of the medium is normally not necessary. The oleophilic reaction medium can comprise any stable, inert, organic oil having a viscosity ranging from 50 to 1000 SUS at 38C (100F) and preferably from 50 to 350 SUS at 38C (100F).

Examples of stable organic oils which may be employed include a wide variety of hydrocarbon lubricating oils such as naphthenic base, paraffmbase, and' mixed base lubricating oils. Other oleophilic oils include oils derived from coal products and synthetic oils, e.g., alkylene polymers (such as polymers of propylene, butylene, etc., and mixtures thereof), alkylene oxide-type polymers (e.g., alkylene oxide polymers prepared by polymerizing alkylene oxide, e.g., propylene oxide polymers, etc., in the presence of water or alcohols, e.g., ethyl alcohol), liquid esters of acids of phosphorus, alkyl benzenes, polyphenols (e.g., biphenols and terphenols), alkyl biphenol ethers, polymers of silicon, e.g., hexyl(4-methyl-2-pentoxy)disilicone, poly(methyl)siloxane, and poly(methylphenyl)- siloxane, etc. The oleophilic lubricating oils may be used individually or in combinations, whenever miscible or whenever made so by use of mutual solvents.

When concentrates are desired, the viscosity of the overbased sulfonate in the oleophilic reaction medium is generally too high for normal processing. In these instances, it is preferred that a light hydrocarbon diluent be employed to reduce the viscosity of the reaction medium. The diluent may be aliphatic or aromatic and boiling below 200C and preferably below 150C. Exemplary aromatic diluents include benzene, toluene, xylene, etc., exemplary aliphatic diluents include cyclohexane, the heptanes, octanes, etc. The diluent should not boil below C and preferably not below C.

At the end of the processing steps, the diluent may be stripped from the system. Any of the conventional stripping techniques may be employed.

PREPARATION OF BORATE DISPERSION The alkali metal borate dispersion may be prepared, in a preferred embodiment, by the following steps: a suitable reaction vessel is charged with the alkali metal carbonate overbased metal sulfonate within the oleo philic reaction medium .(typically the hydrocarbon medium employed to prepare the overbased metal sulfonate). The boric acid is then charged to the reaction vessel and the contents vigorously agitated.

The reaction is conducted for a period of 0.5 to 7 hours, usually from 1 to 3 hours at a reaction temperature of 20 to 200C, preferably from 20 to 150C and more preferably from 40 to C. At the end of the reaction period, the temperature is raised to 100 to 250C, preferably from 100 to C to strip the medium of any residual alcohol and water. The stripping may be done at atmospheric pressure or under reduced pressure of 700 mm. to 10 mm.Hg.

The amount of boric acid charged to the reaction medium depends upon what type of alkali metal borate is desired. If a tetraborate is desired 2 molar parts of boric acid is charged per molar equivalent part of over- 7 based alkali metal (e.g., 4 molar parts of boric acid for each molar part of sodium carbonate). Generally, from 1 to 3 molar parts of boric acid are charged to the reaction medium for each molar equivalent part of overbased alkali metal.

The amount of alkali metal borate which may be present in the oleophilic lubricating oil may vary from 0.1 to 65 weight percent depending on whether a concentrate or final lubricant is desired. Generally, for concentrates, the borate content varies from 20 to'50 weight percent, and preferably from 35 to 45 weight percent. For lubricants, the amount of borate generally varies from 0.1 to 20 weight percent and preferably from 4 to 15 weight percent.

The preferred borate dispersions are sodium or potassium metaborates, having from to 8 waters of hydration (preferably 1 to 5) and prepared from an overbased sodium, potassium, calcium or barium petroleum sulfonate. Particularly preferred is a borate dispersion of sodium metaborate having 0 to 2 waters of hydration and prepared from an overbased calcium sulfonate.

In a particularly preferred embodiment, the alkali metal tetraborates are prepared from an overbased metal sulfonate and converted into a metaborate by the subsequent reaction with two molar parts of an alkali metal hydroxide per molar part of said alkali metal tetraborate. This is the preferred method for preparing the metaborates since a charge ratio of one molar part of boric acid per molar equivalent part of metal carbonate in the overbased metal sulfonate tends to form a mixture of prefominantly a metal tetraborate and overbased metal carbonate. The reaction conditions may be the same as that described for the preparation of the alkali metal carbonate overbased alkali or alkaline earth metal sulfonate.

The water tolerance properties of the metal borate dispersion may be improved by the addition of a lipo philic nonionic surface active agent to the lubricant. The lipophilic nonionic surface-active agents include those generally referred to as ashless detergents. Preferably the nonionic surfactants will have an HLB value (hydrophilic lipophilic balance) below about 7 and preferably below about 5. These ashless detergents are well known in the art and include hydrocarbyl-substituted amines, amides and cyclo-imides. The hydrocarbyl group or groups act as the oil-solubilizing group, and the amine, amide or imide groups act as the polarliquid'solubilizing group.

Aprincipal class of lipophilic nonionic surface active agents is the N-substituted alkenyl succinimides, derived from alkenyl succinic acid or anhydride and alkylene polyamines. These compounds are generally considered to have the formula carbon atoms), Alk is an alkylene radical of 2.to 10, preferably 2 to 6. carbon atoms, A is hydrogen or an alkyl having from 1 to 6 carbons; n is an integer from 0 to 6', preferably 0 to 3 and m is an integer from 0 to l and preferably 0. (The actual reaction product of alkenyl succinic acid or anhydride and alkylene polyamine will comprise a mixture of compounds, including succinamic acids and succinimides. However, it is customary to designate this reaction product as succinimide of the described formula, since that will be a principal component of the dispersant mixture. (See U.S. Pat. Nos. 3,202,678; 3,024,237; and 3,172,891.)

These N-substituted alkenyl succinimides can be prepared by reacting maleic anhydride with an olefinic hydrocarbon, followed by reacting the resulting alkenyl succinic anhydride with the alkylene polyamine. The R radical of the above formula, that is, the alkenyl radical, is preferably derived from an olefin containing from 2 to 5 carbon atoms. Thus, the alkenyl radical may be obtained by polymerizing an olefin containing from 2 to 5 carbon atoms to form a hydrocarbon having a molecular weight ranging from about 400 to 3000. Such olefins are exemplified by ethylene, propylene, l-butene, 2-butene, isobutene, and mixtures thereof. Since the methods of polymerizing the olefins to form polymers thereof is not the invention described herein, any of the numerous processes available in the art can be used.

The alkylene amines used to prepare the succinimides are of the formula wherein y is an integer from 1 to 10, preferably 1-6, A and R1 are each a substantially hydrocarbon radical having from 1 to 6 carbons or hydrogen, and the alkylene radical Alkl is preferably a lower alkylene radical having less than about 8 carbon atoms. The alkylene amines include ethylene amines, propylene amines, butylene amines, pentylene amines, hexylene amines, heptylene amines, octylene amines, other polymethylene amines, and also the cyclic and the higher homologs of such amines as piperazines and amino-alkyl-substituted piperazines. They are exemplified specifically by: propylene diamine, decamethylene diamine, octamethylene diamine, di(heptamethylene) triamine, tripropylene tetramine, trimethylene diamine, di(- trimethylene) triamine, 2-heptyl 3-(2-aminopropyl) imidazoline, 1,3-bis(2-aminoethyl) imidazoline, l-(2- aminopropyl)piperazine, l-4-bis(2-aminoethyl)piperazine, and 2-methyl-l-(2-aminobutyl)piperazine. Higher homologs such as are obtained by condensing two or more of the above-illustrated alkylene amines likewise are useful.

The term ethylene amine is used in a generic sense to denote a class of polyamines conforming for the most part to the structure n mca cnwm n in which R2 is a lower alkyl radical of 1 to 4 carbon atoms or hydrogen and y is defined above. Thus it includes, for example, ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylcne hexamine, 1,2-diaminopropane, N,N-di( l-methyl-2-aminomethyl)amine, etc.

A second group of important nonionic dispersants comprises certain pentaerythritol derivatives. Particular derivatives which find use in this invention are those in which pentaerythritol is combined with a polyolefin and maleic anhydride or with a polyolefin and a phosphorus sulfide. The polyolefins are the polymers of monomeric olefins having 2 to 6 carbon atoms, such as polyethylene, polypropylene, polybutene, polyisobutylene, and the like. Such olefins generally contain a total of to 250 carbon atoms and preferably to 150 carbon atoms. The phosphorus sulfides include P2S3, P255, P457, P483 and related materials. Of these, P255 (phosphorus pentasulfide) is preferred principally because of its ready availability.

Other nonionic emulsifiers which may be used include polymethacrylates and copolymers of polymethacrylate or polyacrylate with vinyl pyrrolidone, acrylamide or methacrylamide.

1f the lipophilic nonionic surface-active agent is employed, it will generally be present in about 0.01 to 5 weight percent, more usually from about 0.1 to 3 weight percent, of the final composition. The actual amount of dispersant required will vary with the particular dispersant used and the total amount of borate in the oil. Generally, about 0.001 to 1, more usually about 0.01 to 0.5, part by weight of nonionic surface-active agent will be used per part by weight of the borate. 1n the concentrates the mixture concentration will be based on the relationshipto borate rather than on the fixed percentage limits of the lubricant, noted above. Generally, the upper ranges of the nonionic surface active agent concentration will be used with the upper ranges of the alkali metal borate concentration.

Other materials may also be present as additives in the composition of this invention. Such materials may be added for enhancing some of the properties which are imparted to the lubricating medium by the alkali metal borate or providing other desirable properties to the lubricating medium. These include additives such as rust inhibitors, antioxidants, oiliness agents, viscosity index improvers, etc. Usually, these will be in the range from about 0.1 to 5 weight percent, preferably in the range from about 0.1 to 2 weight percent, of the total composition. An antifoaming agent may also be added with advantage. The amount required will generally be about 0.5 to 50 ppm, based on the total composition.

The borate dispersions are preferable employed in lubricating oils, such as, gear and bearing oils, cutting oils, pneumatic oils, greases, etc. The concentration of the alkali metal borate present within the lubricating oil (oleophilic reaction medium) may vary from 0.1 to 20 weight percent depending upon the particular application.

The borate dispersion may also be employed in a grease to impart extreme pressure properties. The grease composition may be prepared by adding a thicknening agent to the borate dispersion in the oleophilic lubricating oil. The thickening agent may be added directly to the borate dispersion or produced in-situ" within the oleophilic oil. Typical thickening agents which may be, employed include organic or metal organic thickener s such as polyurea, alkali metal terephthalamate, lithium hydroxystearate, calcium complex soap, aluminum complex soap, polymeric thickener or combinations thereof.

Exemplary polyurea greases which may be employed are disclosed in U.S. Pat. No. 3,243,372. These greases are prepared by reacting, within the lubricating oil to be thickened, a polyamine having from 2 to 20 carbons, a diisocyanate having from 6 to 16 carbons and a monoamine or monoisocyanate each having from 10 to 30 carbons. Typically, these greases contain from 5 to 15 weight percent of the polyurea thickener although lesser amounts may be used if other thickening agents are present. A particularly preferred polyurea is a tetraurea prepared by reacting one molar part of ethylene diamine with two molar parts of tolylen diisocyanate and two molar parts of a monoamine having from 16 to 20 carbons.

Exemplary sodium terephthalamate greases are disclosed in U.S. Pat. Nos. 2,820,012 and 2,892,778. These greases may be prepared by reacting a monoester of terephthalic acid with an alkali metal base in the presence of a solvent. A particularly preferred grease contains from 8-15 weight percent of a sodium N-(hydrocarbyl) terephthalamate having from 5 to 24 carbons in the hydrocarbyl group such as sodium N- octadecyl terephthalamate.

The lithium hydroxy stearate greases are the most widely employed multi-purpose grease. These greases have the properties which render them particularly suitable for use in the practice of this invention. The lithium thickening agent is typically prepared by reacting lithium hydroxide with hydrogenated castor oil and is present within a lubricating oil at a concentration of 10 to 20 percent.

Another class of high temperature greases which may be employed is the calcium complex grease. These greases are composed of 520 percent of a calcium soap, e.g., calcium hydroxystearate, 4-20 percent of calcium acetate and 1-10 percent of calcium carbonate. A small amount of calcium hydroxide may also be employed. Exemplary greases of this type are described in U.S. Pat. Nos. 3,186,944 and 3,159,575.

Exemplary aluminum complex greases are described in U.S. Pat. Nos. 3,476,684 and 3,514,400. These greases are prepared by incorporating into a lubricating oil from 5-20 percent of the reaction product of a long chain fatty acid, an aromatic acid and aluminum isopropoxide.

The amount of thickener employed in making the greases of this invention varies depending upon the type thickener, type of lubricating oil, hardness of the grease desired and the presence of other additives. When greases having the preferred hardness of No. 2-4 NLGl (ASTM work penetration varying from 340 to are employed, the amount of thickener generally varies from 5 to 25 weight percent and more usually from 8 to 15 weight percent of the grease composition.

EXAMPLE 1 159C (318F) to 248C (478F), ASTM D 447 distillation) is-collected as feed for the second stage alkylation with a mixture of straight chain l-olefins. The average molecular weight of the above branched chain alkylibenzene .is l64.This correspondsto an'average of 6 sulfonate and heated for onfhotirqrh phases are i allowed toseparate and the aqueous phase drawn off.

carbon atoms per alkyl group in themixture. Theover- Average mol weight Average number of carbon atoms per molecule 1 I 19 Olefin distribution, weight percent: C17 2 C18 22 C19 39 C20 32 C21 '5 Reaction conditions: 2 Temperature 38C 100F) Monoalkylbenzene to alphai olefin, mol ratio 2.l Hydrocarbon to HF ratio.

volume 2.3-1

After reaction the settled product is separated into an organic phase and a lower HF acid' phase. The crude dialkylbenzene organic phase is washed and then fractionated by distillation. A minor amount of forecut, mainly monoalkylbenzene, is collected up to an overhead temperature of about 232C (450F) at mm.Hg. The balanceof the distillate is the desired product, and has an average molecular weight of about 405. The difference between the average. carbon atom content of the alkyl-chain types is about 13.

The dialkylbenzene is charged to a stirred reaction vessel fitted for temperature control along with 130 neutral oil which is substantially free of sulfonatable material. The volume ratio of the two materials is 3% to 4, "respectively, and .to this mixture is added, over a period of severalhours, 2 volumes of 25% oleum. The

reaction temperature is maintained at about 38C (100F). Two phases developed in the settled mixture, the'lower being a spent mineral acid phase and the upper being thedesired' sulfonic acid phase- The'separated sulfonic acid-oil mixture is then neutralized with one volume of 50% aqueous caustic diluted with volumes'of aqueous Z-butanol. During the neutralization the temperature is maintainedbelow about 43C (110F), and after completion thereof the neutral. solution is heated and maintained at 60C (1.40F)during a second phase separation. Two phases developed, a lower brine-alcohol solution and an upper neutral alcohol-sodium sulfonate solution.

EXAMPLE 2v The preparation of a neutral calcium sulfonate is The sulfonate is washedthree additional times with waterand one time with an aqueous isobutyl alcohol solution. The mixture is heated to 1 12C to remove any residual water and isobutyl alcohol. SOD-milliliters of toluene is added to the sulfonate and the admixture filtered through Ce lite 512. The product isstripped at 185C under 3 mm.Hg pressure to yield 740 grams of neutral calcium sulfonate. Analysis of the product reveals Wt metal EXAMPLE 3 This example is presented to illustrate the preparation of a sodium carbonate .overbased calcium sulfonate which may be employed to prepare the borate dispersions of this invention. A neutral sodium sulfonate is prepared by sulfonating a 480 neutral oil (RPM 480) in a manner as described in Example 1 and neutralizing the resultingorganic sulfonic acid with sodium hydroxide. The resulting sodium sulfonate is then subjected to calcium metathesis as described in Example 2 to yield a neutral calcium sulfonate (calcium content of about 1.67 weight percent).

- A 2-liter flask is charged with 200 grams of the neutral calcium sulfonate and 750 ml of an aliphatic hydrocarbonv diluent having a .boiling range of 158C to 202C and containing 17 percent aromatics. The solution is heated to C and a solution of 60 grams of sodium hydroxide in 300 ml of methanol 'are added over a 138-minute period at 110C. i

Uponcompletion of the sodium hydroxide addition the temperature is raised to C and carbon dioxide is passed into the solution at a rate equal to its maximum carbon dioxide absorption. The carbonation continued for 60 minutes at 130C and then the contents of the flask are heated to C. A total of 38 grams of CO2 are absorbed. The contents are cooled and filtered. :The filtered product is then stripped to C at 5 mm of Hg pressure. A total of 229 grams of product is recovered. The product had an alkalinity value of 253 mg KOH/gm.

EXAMPLE 4 A two-.liter flask is chargedwith 200 grams of a neutral calcium sulfonate of the type described in Example 3 along with 750 milliliters of an aliphatic hydrocarbon diluent having a boiling range from 1 58C to 202C and containing 17 percent aromatics. A solution of 60 grams of sodium hydroxide in 300 milliliters of methanol is added to the flask through a dropping funnel. The temperature is maintained between 23C and 40C during the addition which took 69 minutes. Simultaneously with. the NaOH addition, carbon dioxide is passed through the flask contents ata'rate equal to its maximum carbon dioxide. absorption. 'Carbonation continued for fifteen minutes after the addition of the' sodium hydroxide/methanol solution had stopped. A

uct is recovered. The product has an alkalinity value of 259 mg KOH/g.

EXAMPLE This is another example demonstrating the preparation of a sodium carbonate overbased calcium sulfonate which may be used to prepare the borate dispersions of this invention. A neutral sodium sulfonate is prepared by sulfonating a 480 neutral oil (RPM 480) in a manner as described in Example 1 and neutralizing the resulting organic sulfonic acid with sodium hydroxide. The resulting sodium sulfonate is then subjected to calcium metathesis as described in Example 2 to yield a neutral calcium sulfonate calcium content of about 1.67 weight percent.

A 2-liter flask is charged with 200 grams of the neutral calcium sulfonate and 750 ml of an aliphatic hydrocarbon diluent of the type described in Example 3. Contents of the flask are heated to 110C and a solution of 60 grams of sodium hydroxide in 300 ml of methanol is introduced into the flask over an 82-minute period at 110C. One minute after the start of the sodium hydroxide addition, carbon dioxide is bubbled into the flask contents at a rate equivalent to that of the sodium hydroxide addition, until a total of 41 grams of carbon dioxide are absorbed. At the end of the sodium hydroxide addition, the temperature is increased to 140C and 507 ml are taken off overhead.

The product is cooled, filtered and stripped to a temperature of 175C under 5 mm.l-lg pressure. A total of 271 grams of product is recovered. The alkalinity value is 302 mgKOl-l/g, and the base ratio is 10.611.

EXAMPLE 6 This example is presented to illustrate the preparation of a sodium carbonate overbased sodium sulfonate, 140 grams of a 57 weight percent sodium sulfonate solution is butanol and prepared by the method of Example 1 are charged to a 2-liter flask along with 325 grams of a 37.5 wt sodium sulfonate solution in butanol and prepared by neutralizing a sulfonated 480 neutral hydrocarbon oil with sodium hydroxide. The contents are heated to 165C under 600 mm vacuum and 263 grams are taken off overhead.

Thereafter 750 milliliters of an aliphatic hydrocarbon diluent described in Example 3 are charged to the flask. The solution is heated to 110C and 60 grams of sodium hydroxide dissolved in 300 milliliters of methanol are slowly added to the flask over a lO0-minute period at 110C. Simultaneously, carbon dioxide is bubbled into the solution at a rate equivalent to that of the sodium hydroxide addition. After completion of the sodium hydroxide addition, the contents are heated to 150C with the carbon dioxide flow continued for 10 additional minutes. A total of 515 milliliters are taken off overhead. A total of 45 grams of carbon dioxide is absorbed. The resulting sodium carbonate overbased sodium sulfonate solution is filtered and the filtrate stripped to a temperature of 175C at 5 mm mercury pressure. A total of 282 grams of product are recovered with an alkalinity value of 299 mg KOH/gm.

EXAMPLE 7 A 2-liter flask is charged with 280 grams of a sodium carbonate overbased calcium sulfonate prepared by the method of Example 5 (alkalinity value of 308), 600 ml of an aliphatic hydrocarbon solvent described in Example 3 and 95 grams of boric acid. The contents of the 0 tent 7.6 weight percent. Carbon dioxide content value 215 0.23 weight mg.KOH/g.

percent; alkalinity EXAMPLE 8 A 2-liter flask is charged with 140 grams of a secbutanol solution containing 57.4 weight percent of a neutral sodium sulfonate prepared by the method of Example 1 and 325 grams of a sec-butanol solution containing 37.5 weight percent of a neutral sodium sulfonate prepared by sulfonating a 480 neutral oil (RPM 480) and neutralizing with sodium hydroxide. The contents are stripped of 262 grams of alcohol. Thereafter, 750 ml of a petroleum aliphatic thinner of the type disclosed in Example 3 are mixed with the contents of the flask. Flask contents are heated to C and a solution of 60 grams of sodium hydroxide in 300 ml of methanol are added to the flask over a 93-minute period at 1 10C. Simultaneously, carbon dioxide is bubbled into the flask contents at a rate equivalent to that of the sodium hydroxide addition until a total of 38 grams of C02 have been absorbed. The temperature is raised to 150C and 515 ml are taken off overhead. The reaction mixture is allowed to cool to 60C and, 93 grams of boric acid are added, and the temperature raised to C over a one-hour period. The contents are allowed to cool under a pressure of 160 mm of mercury. Thereafter, an additional 93 grams of boric acid are charged to the flask contents and the temperature raised to C over a 70-minute period. A vacuum of 600 mm of mercury is applied to the flask to cool the product. Product is filtered and stripped to 165C at 5 mm of mercury pressure. 367 grams of product are recovered. Analysis of the product reveals an alkalinity value of 233 mg.KOH/g; a boron content of 7.7 weight percent and a carbon dioxide content of 0.12 weight percent.

EXAMPLE 9 The example is presented to demonstrate the preparation of an exemplary potassium borate dispersion. A 2-liter flask is charged with (1) grams of a secbutanol solution containing 57.4 weight percent of a neutral sodium sulfonate prepared by the method of Example 1 and 325 grams of a sec-butanolsolution containing 37.5 weight percent of a neutral sodium sulfonate prepared by sulfonating a 480 neutral oil (RPM 480) and neutralizing with sodium hydroxide. The contents are stripped of 262 grams of alcohol. 750 ml of a petroleum aliphatic thinner of the type employed in Example 3 are mixed with the contents of the flask. Flask contents are then heated to 110C and a solution of 107 grams of potassium hydroxide in 300 ml of methanol are added to the flask over a 94-minute period at 1 10C. Simultaneously carbon dioxide is bubbled into the flask contents at a rate equivalent to that of the potassium hydroxide addition until a total of 43 grams of CO2 are absorbed. The temperature is raised to C and 525 ml are taken off overhead. The reaction mixture is allowed to cool to 60C and 102 grams of boric acid are charged to the flask, the temperature raised to 135C in approximately 45 minutes. The temperature is maintained at 135 for an additional 30 minutes, then the contents are allowed to cool under a pressure of 160 mm of mercury. 63 ml are taken off overhead. An additional .102 grams of boric acid is added to the flask and the temperature slowly raised to 145C in one hour. The reaction mixture is cooled, filtered and stripped to 165C under a pressure of mm of mercury. 396 grams of product is recovered. Analysis of the product reveals that it has an alkalinity value of 223, a boron content of 7.1 weight percent and a carbon dioxide content of 0.62 weight percent.

EXAMPLE A 2-liter flask is charged with 280 grams of sodium carbonate overbased calcium sulfonate having an alkalinity value of 308 and prepared by the method'of Example 5 along with 600 ml of an aliphatic hydrocarbon thinner of the type described in Example 3 and 95 grams of boric acid. The contents of the flask are slowly heated to 120C over a one-hour period. The contents are slowly cooled to 60C by applying a vacuum of 600 mm of mercury to the flask contents. A total of 59 ml are recovered overhead. Thereafter, 95 grams of boric acid are charged to the flask and heated to 120C over a one-hour period. The contents are then cooled to 65 under a pressure of 160 mm and 87 ml are taken off overhead. Thereafter, a third batch of 95 grams of boric acid are charged to the flask and the contents heated to 140C in 1% hours. A vacuum of 600 mm of mercury is slowly applied to the flask and the contents allowed to cool. 200 ml are taken off overhead. The product wasfiltered and stripped to 165C at 5 mm of mercury pressure. 417 grams of product was recovered. The product is analyzed and found to have an alkalinity value of 187 mg KOH/g; a boron content of l 1.7 weight percent and carbon dioxide content of 0.01 weight percent.

EXAMPLE 1 l A 2-liter flask is charged with 380 grams of sodium carbonate overbased calcium sulfonate as described in Example 5, along with 400 milliliters of an aliphatic thinner of the type described in Example 3. The contents of the flask are heated to 40C and thereafter 122 grams of boric acid are added. The temperature of the solution is slowly raised to 150C in approximately 105 minutes. The product is then cooled, filtered and stripped to recover 435 grams of product. The filtration and stripping step is described in Example 8. Analysis of the product reveals an alkalinity value of 262 mg KOH/g, a boron content of 5.36 weight percent and a carbon dioxide content of 4.27 percent. The high carbon dioxide content reveals that the product is a mixture of sodium tetraborate and sodium carbonate.

293 grams of this product along with 500 milliliters of an aliphatic thinner of the type described in Example 3 are charged to a two-liter fournecked flask. Thereafter 82 grams of additional boric acid are added to the flask. The contents are slowly heated to a temperature of 135C over an hour period. The contents are cooled and then heated to 1 10C and a solution of 51 grams of sodium hydroxide in 260 milliliters of methanol are added over a 70-minute period at 1 10C. An additional 140 milliliters of aliphatic thinner of the type described in Example 3 are then added to the flask and the temperature of the contents raised to 150C. The product is then filtered and stripped in the manner described in Example 8. A total of 364 grams of sodium metaborate product is recovered. Analysis of the product reveals an alkalinity value of 386 mg KOH/g and a boron content of 8.06 weight percent.

EXAMPLE 12 This example is presented to illustrate the preparation of a metaborate dispersion. A 2-liter flask is charged with 132 grams-of a sodium sulfonate solution prepared by neutralizing a sulfonated 480 neutral oil in a manner described in Example 3. The sodium sulfonate solution contains 38 weight percent sodium sulfonate and 62 weight percent butanol. 133 grams of RPM Hydrocarbon Neutral Oil having a viscosity of 1 26 SUS at F are added to the flask. The contents of the flask are'stripped to 165C and 600 mm mercury vacuum and 81 grams are taken off overhead. Thereafter, 17 grams of a polyisobutenyl succinimide dispersant (formed by the reaction of polyisobutenyl succinic anhydride with tetraethylene pentamine 'with the succinimide product containing 2.2 percent nitrogen) and 750 milliliters of an aliphatic diluent of the type described in Example 3 are added to the flask. The contents are heated to 1 10C under vigorous agitation and asolution of -50 grams of sodium hydroxide-4n 250 milliliters of methanol are slowly added over an 80- minute period at 1 10C. Simultaneously with the addition of the sodium hydroxide solution, carbon dioxide is bubbled into the flask contents at a rate equivalent to that of the sodium hydroxide addition. After 28 grams of carbon dioxide are absorbed, the flask contents are heated to 150C and 455 milliliters are taken of overhead;

The contents are cooled to 60C and two aliquots of 78 grams of boric acid are added (a total of 156 grams are added). The temperature is raised to C then cooled to 60C after the first aliquot and the temperature raised to C after the addition of the second aliquot. A slight vacuum is applied and a totalof 161 milliliters are taken off overhead. The resulting product is a tetraborate.

To convert the tetraborate to a metaborate, the flask contents are diluted with 250 milliliters-of the aliphatic diluent described above and heated to 1 10C. Thereafter, a solution of 50 grams of sodium hydroxide in 250 milliliters of methanol are slowly added over an eightyminute period at 110C.

The temperature is raised to C and thereafter the reaction mixture is cooled to 75C. The product is filtered and then stripped to C at 5 mm Hg. pressure. i

382 grams of product are recovered which upon analysis revealed Nitrogen Content (wt 0.089

CO2 (wt q 0.04

Boron (wt 7.68

Alkalinity value 355 mg KOH/gm EXAMPLE 13 The procedure of Example 12 is repeated except that the 132 grams of sodium sulfonate solution is replaced by 50 grams of a calcium sulfonateprepared by the method of Example 3 The calcium sulfonate is overbased by the procedure of Example 3 and reacted with 17 boric acid to form the tetraborate and thereafter converted to the metaborate. A total of 365 grams of product is recovered and analysis reveals the following:

Nitrogen Content (wt 71) 0.08l

CO2 (wt O.l7

Calcium (wt 0.05

Boron (wt%)' 7.l

Alkalinity value 339 mg KOH/gm EXAMPLE 14 Temperature l30F Speed I200 rpm Load kg Duration of Test l Hour In each test, three one-half-inch diameter steel balls posed of the aforesaid base oil containing a sodium carbonate overbased sulfonate as prepared by Example 6. Test Lubricant C is the aforesaid base oil containing 10 wt. of a sodium metaborate prepared by the method of U.S. Pat. No. 3,313,727 (Example I of patent) and containing a neutral calcium petroleum sulfonate. Test Lubricant D is the aforesaid base oil containing sodium borate prepared by the method of Example 7. Test Lubricant E is the aforesaid base oil containing a sodium borate produced by the method of Example 8. Test Lubricant F is the aforesaid base oil containing a potassium borate produced by the method of Example 9. Test Lubricant G is composed of the aforesaid base oil containing a sodium borate produced by the method of Example IQ. Test Lubricant H is the aforesaid base oil containing a sodium borate prepared by the method of Example 12. Test Lubricant I is the aforesaid base oil containing a sodium borate prepared by the method of Example 13. The table following depicts the test results of the above test lubricants in the Four Ball and Timken Tests. Also shown in the table is the compatibility of the metal borate with various additives. In order to pass this test the borate containing oil must not gel in the presence of an equal volume of Chevron Multiservice Gear Lube 90 after 65 hours at 180F, and must be clear in the presence of 2 wt. of a conventional sulfurized calcium phenate after 65 hours at 180F.

TABLE I Extreme Pressure Properties Test Test Borate Additive 4-Ball Test Timkenf" Compatibility No. Sample Type Cone. (Wt.%) Wear Weld (Pass Lbs.) Lbs. Pass/Fail l. A None 0.68 .130 5 2. B Na CO 13.5 0.45 20 3. C NaBO 10 0.25 225 lOO Fail 4. D Na,B O-, 8.2 0.5l 195 65 Pass 5. E Na B O, I 0 0.45 I 95 I00 Pass 6. F K 3 0, 8.3 0.40 I85 I00 7. G Na 03(B O l0 0.52 I90 55 Pass 8. H NaBO, lo 0.26 255 I00 9. I NaBO, 10 0.29 250 I00 Pass are clamped together and immersed in the test lubricant. A fourth ball is then rotated at the selected rpm in We claim:

contact with the other three balls. The 20-kg load is applied to the rotating ball, forcing the same against the three stationary balls. Test is run for one hour and at the end of this run, the three'stationery balls are observed for wear scars. The average scar size in millimeters is reported. The size of the scar is indicative of the extreme pressure character of the lubricant with a smaller scar representing a superior extreme pressure lubricant.

In a second Four-Ball Test, increasing load is applied to the fourth ball until the four balls seize or weld together. The load at the weld point is noted and the load immediately preceding the weld is noted. The higher the load applied to the ball without welding, the better the extreme pressure properties of the lubricant.

Another test which determines the extreme pressure capabilities of the lubricant is the so-called Timken Test. The procedure and mechanics of this test are set forth in ASTM 2782-69T. The Timken Test reveals the antiwear characteristics of the lubricant with a higher load and higher contact pressure indicating the better antiwear properties.

The test lubricants employed in this example include the following:

Test Lubricant A is a base oil comprising SAE 90 Gear Oil without additives. Test Lubricant B is com- 1. A process for preparing a particulate alkali metal borate dispersion which comprises contacting an alkali metal carbonate overbased alkali or alkaline earth metal sulfonate with boric acid within a stable inert oleophilic liquid reaction medium, wherein said contacting is conducted at a temperature of 20 to 200C for a period of 0.5 to 7 hours and wherein the molar ratio of boric acid to alkali metal carbonate is from I to 2. The process defined in claim 1 wherein said contacting is conducted at a temperature of 40 to I25C for a period of l to 3 hours.

3. The process defined in claim 2 wherein from one to two molar parts of boric acid are contacted for each molar equivalent part of alkali metal carbonate overbased alkali or alkaline earth metal sulfonate.

4. The process defined in claim 3 wherein said alkali metal carbonate is sodium or potassium carbonate and said alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.

5. The process defined in claim 4 wherein said particulate alkali metal borate has from 0 to 8 waters of hydration.

6. The process defined in claim 5 wherein said alkali metal borate is a sodium metaborate, wherein said alkali metal carbonate is sodium carbonate, and said hydration.

alkali or alkaline earth metal sulfonate is calcium sulfonate. a

7. A process for preparing a particulate alkali metal metaborate dispersion which comprises contacting at a temperature of 2010 200C for a periodof 0&5 to 7 hours two molar parts of boric-acid? with each molar equivalent part of "an 'aIkali-meta'l carbonate overbased alkali or alkaline 'earth sulfonate within a== stable inert oleophilic liquid reac'tionm'ed-ium to form an intermediate alkalimetaltetraborate dispersion=andthereafter contacting said alkali metal tetrabor'ate with two niolar parts of an alkal'imetal hydroxide permolar part of said alkali metal tetraborate to prepare an alkali metal metaborate dispersion; i I

8 The process defined in claim 7 wherein said alkali metal carbonate i's'sodi um or potassium carbohate and said'alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonatef '9. Theprocess dfined'iitclaim 8 wherein a lipophilic nonionic surface'active agent is also present during the contacting of said alkali metal tetraborate and said alkali metal hydroxide;

10 The processdefinediri claim 9 wherein said lipophilic nonionic surface active age nt is an N-substituted alkyl succinimide derived from reacting alkenyl succinic acid or anhydride with an alkylene polyamine;

11. A particulate di spe'rsion of an alkali metal borate having a particle size below about 0.1 micron wherein saidpart iculat'e alkali'metal borateis'prepared by contacting at a temperature of 20 to 200C and for a Vperiod1of Q, 5 to' /,hours boric acid with an alkali metal carbonate overbased metal sulfonate within a stable inert oleophilic liquid reaction medium wherein the molar.,ratio of said boric acid to said alkali metal car.-

bonate is from 1 to 3. v

12. The composition defined in claim 1 1 wherein said alkali metal carbonate is sodium or potassium carbonate and, wherein saidalkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.

13. The composition defined in claim 12 wherein said particulate alkali metal borate has from 0 to 8 waters of 14. A particulate dispersion of an alkali metalborate prepared by contacting ata temperature of 20'to 200C-and for a period 060.5 to 7. hours two :molar parts of boric acid with each molar. equivalent part of alkali metal tetraborate to form ant-alkali metalmetaborate dispersion; n Y a 15. The composition defined inclaim l4 wherein said alkali metal carbonate is sodium or potassium carbonate and wherein said alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.

16. The composition defined in claim 14 wherein said alkali metal carbonate is sodium carbonate and wherein said overbased alkali metal or alkaline, earth metal sulfonate is calcium sulfonate.

l7. Composition defined in claim 15 wherein an N-substituted alkenyl succinimide derived from the reaction of alkenyl succinic acid or anhydride with an alkylene polyamine is present in said stable inefrt oleophilic liquid reaction medium! I, 18. A lubricating composition com'mprisinga major portion of ahydrocarbon oil of lubricating viscosity and from 0.1 to 'weight percent of particulate alkali metal borate dispersed iri said oil, said alkali metal borate being prepared by reacting at a'temp'er'ature of 20 to 200 C and for aper'iod of 0.5 to hours an alkali metal carbonate overbased alkali or alkaline earth wherein said alkali metal carbonate is sodium or potasan alkali metal carbonate overbased alkali or alkaline earth metal sulfonate within-astable inertoleophilic liquid reaction medium to form an alkali metal tetraborate dispersion which is then reacted with two molar parts of an'alkali metal hydroxide per molar part of said sium carbonate and said alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.

20. The composition defined in claim 18 wherein said particulate alkalifrnetal borate has a particle size of less "than 0.1 microns. r

21. A grease composition comprising a' major portion of a lubricating oil, from 5 to 25 weight percent of an organic or metal: organic thickener selected from the group consisting ofpolyurea, alkali metal terephthalamate, lithium hydroxy stearate, calcium complex soap and aluminum complex soap,'and from (H to 20 weight percent of an alkali m etaljborate prepared by reacting at a temperature of 20 to 200C and for a period of 0.5 to 7 hours an: alkali metal carbonate overbased alkali or alkaline earth metalsulfonate with boric acid, wherein the molar ratio of said boric .acid to' said alkali metal carbonate is fromg l to 3,. .1 v h I 22. The greasecomposition defined in claim 21 wherein said. alkali metal .carbonateis sodium carbonate and said, alkali or. alkaline earth metalsulfonate is sodium, calcium or barium-sulfonate. H 4

23. The grease composition defined in claim 22 wherein said organic .or metal orgapic thickener is a polyurea thickenen' 

1. A PROCESS FOR PREPARING A PARTICULATE ALKALI METAL BORATE DISPERSION WHICH COMPRISES CONTACING AN ALKALI METAL CARBONATE OVERBASED ALKALI OR ALKALINE EARTH METAL SULFONATE WITH BORIC ACID WITHIN A STABLE INERT OLEOPHILIC LIQUID REACTION MEDIUM, WHEREIN SAID CONTACTING IS CONDUCTED AT A TEMPERATURE OF 20* TO 200*C FOR A PERIOD OF 0.5 TO 7 HOURS AND WHEREIN THE MOLAR RATIO OF BORIC ACID TO ALKALI METAL CARBONATE IS FROM 1 TO
 3. 2. The process defined in claim 1 wherein said contacting is conducted at a temperature of 40* to 125*C for a period of 1 to 3 hours.
 3. The process defined in claim 2 wherein from one to two molar parts of boric acid are contacted for each molar equivalent part of alkali metal carbonate overbased alkali or alkaline earth metal sulfonate.
 4. The process defined in claim 3 wherein said alkali metal carbonate is sodium or potassium carbonate and said alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.
 5. The process defined in claim 4 wherein said particulate alkali metal borate has from 0 to 8 waters of hydration.
 6. The process defined in claim 5 wherein said alkali metal borate is a sodium metaborate, wherein said alkali metal carbonate is sodium carbonate, and said alkali or alkaline earth metal sulfonate is calcium sulfonate.
 7. A process for preparing a particulate alkali metal metaborate dispersion which comprises contacting at a temperature of 20* to 200*C for a period of 0.5 to 7 hours two molar parts of boric acid with each molar equivalent part of an alkali metal carbonate overbased alkali or alkaline earth sulfonate within a stable inert oleophilic liquid reaction medium to form an intermediate alkali metal tetraborate dispersion and thereafter contacting said alkali metal tetraborate with two molar parts of an alkali metal hydroxide per molar part of said alkali metal tetraborate to prepare an alkali metal metaborate dispersion.
 8. The process defined in claim 7 wherein said alkali metal carbonate is sodium or potassium carbonate and said alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.
 9. The process defined in claim 8 wherein a lipophilic nonionic surface active agent is also present during the contacting of said alkali metal tetraborate and said alkali metal hydroxide.
 10. The process defined in claim 9 wherein said lipophilic nonionic surface active agent is an N-substituted alkyl succinimide derived from reacting alkenyl succinic acid or anhydride with an alkylene polyamine.
 11. A particulate dispersion of an alkali metal borate having a particle size below about 0.1 micron wherein said particulate alkali metal borate is prepared by contacting at a temperature of 20* to 200*C and for a period of 0.5 to 7 hours boric acid with an alkali metal carbonate overbased metal sulfonate within a stable inert oleophilic liquid reaction medium wherein the molar ratio of said boric acid to said alkali metal carbonate is from 1 to
 3. 12. The composition defined in claim 11 wherein said alkali metal carbonate is sodium or potassium carbonate and wherein said alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.
 13. The composition defined in claim 12 wherein said particulate alkali metal borate has from 0 to 8 waters of hydration.
 14. A particulate dispersion of an alkali metal borate prepared by contacting at a temperature of 20* to 200*C and for a period of 0.5 to 7 hours two molar parts of boric acid with each molar equivalent part of an alkali metal carbonate overbased alkali or alkaline earth metal sulfonate within a stable inert oleophilic liquid reaction medium to form an alkali metal tetraborate dispersion which is then reacted with two molar parts of an alkali metal hydroxide per molar part of said alkali metal tetraborate to form an alkali metal metaborate dispersion.
 15. The composition defined in claim 14 wherein said alkali metal carbonate is sodium or potassium carbonate and wherein said alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.
 16. The composition defined in claim 14 wherein said alkali metal carbonate is sodium carbonate and wherein said overbased alkali metal or alkaline earth metal sulfonate is calcium sulfonate.
 17. Composition defined in claim 15 wherein an N-substituted alkenyl succinimide derived from the reaction of alkenyl succinic acid or anhydride with an alkylene polyamine is present in said stable inert oleophilic liquid reaction medium.
 18. A lubricating composition commprising a major portion of a hydrocarbon oil of lubricating viscosity and from 0.1 to 20 weight percent of particulate alkali metal borate dispersed in said oil, said alkali metal borate being prepared by reacting at a temperature of 20* to 200*C and for a period of 0.5 to 7 hours an alkali metal carbonate overbased alkali or alkaline earth metal sulfonate with boric acid, wherein the molar ratio of said boric acid to said alkaline metal carbonate is From 1 to
 3. 19. A lubricating composition defined in claim 18 wherein said alkali metal carbonate is sodium or potassium carbonate and said alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.
 20. The composition defined in claim 18 wherein said particulate alkali metal borate has a particle size of less than 0.1 microns.
 21. A grease composition comprising a major portion of a lubricating oil, from 5 to 25 weight percent of an organic or metal organic thickener selected from the group consisting of polyurea, alkali metal terephthalamate, lithium hydroxy stearate, calcium complex soap and aluminum complex soap, and from 0.1 to 20 weight percent of an alkali metal borate prepared by reacting at a temperature of 20* to 200*C and for a period of 0.5 to 7 hours an alkali metal carbonate overbased alkali or alkaline earth metal sulfonate with boric acid, wherein the molar ratio of said boric acid to said alkali metal carbonate is from 1 to
 3. 22. The grease composition defined in claim 21 wherein said alkali metal carbonate is sodium carbonate and said alkali or alkaline earth metal sulfonate is sodium, calcium or barium sulfonate.
 23. The grease composition defined in claim 22 wherein said organic or metal organic thickener is a polyurea thickener. 